https://youtu.be/xJn3k1f4BiM

[basic_sintax_loop](Reusable-master/JavaScript/2-loop_1.js) :

loop for
- block of define
    - first (definition of input variables)
    - second (compose predicate)
    - third (sequence expression)

hash
- collection as object with name_field binded to field

[basic_sintax_object](Reusable-master\JavaScript\6-hash.js) :

[basic_sintax_array](Reusable-master\JavaScript\5-array.js) :

iteration for
- array for of
- object for in

[2-middle_2.js](Cheatsheet-master/JavaScript/2-middle_2.js) :

https://www.youtube.com/watch?v=qa-XleqA0JU&feature=youtu.be

function return extends class

[3-scalar_1.js](DataTypes-master\JavaScript\3-scalar_1.js) : 

Number , String is scalar type ! 

Other type is reference type !
 
typeof [] return object
isArray([]) return true 

[7-delete_1.js](DataTypes-master\JavaScript\7-delete_1.js) :

- const a  ==> impossible `delete a`
- delete a identifier 
- delete field of object `delete b.name`

[my_bitFunc.js](DataTypes-master\JavaScript\my_bitFunc.js) :

# N < 2**31-1; n <= 30
## encription bit
- encription base on identity (`a^r^r === a`)
## bitMask  
- biteMask base on identity n<30!:
  - `n < 30`
  - `b[i] = 2 ** n`
  -  `(b1|b2)&b3 === false if b1!=b3 && b2!=b3`
#
    const access_1 = 2;
    const access_2 = 4;
    const access_3 = 8;

    const root_guest_to_1_and_3 = access_1 | access_3;
    const access_2_to_guest = (
        root_guest_to_1_and_3 & access_2 ?
            'guest have access_2' :
            'guest have not access_2' );
        // answer : guest have not access_2

## check for -1 bit
- check for -1  base on identity `~(-1) === 0`
#
    const zero = ~( -1 ); // zero === 0
    if( ~'ardo'.indexOf( 'b' ) ) console.log( 'a is present in ardo ' );
    else console.log( 'b is not present in ardo ' );

## check isInteger 
- ` n === (n^0)`

## conditional(ternary) operator
- check for `null` or `underfine` or `not expected` possible arguments function:
#  
    function greeting( person ){
        let names = person
            ? ( person.name
                ? person.name
                : 'very stranger' )
            : "stranger";
        return "Howdy, " + names;
    }

    const gr = greeting( { name: 'Alice' } );
    const gr2 = greeting();
    const gr3 = greeting( null );
    const gr4 = greeting( { noname: 'jomy' } );

- chain condition
#
function chain_ternary( a ){
    return a ? ( a > 3 ? 'a > 3'
        : a < 3 ? 'a < 3'
            : 'a === 3' )
        : 'a is undefined';
}

const w1 = chain_ternary( 4 ); // 'a > 3'
const w2 = chain_ternary( 2 ); // 'a < 3'
const w3 = chain_ternary();

## void operator

    const a = () => 10;
    const uu = a(); // 10
    const b = void a(); // underfined

[6-switch.js](Conditional-master\Javascript\6-switch.js) :


  - switch in function 
#
      function checkArgs(a){
          switch(a){
              case 'a':{
                  console.log('a - true')
                  return a;
              }
              default:
                  return new Error('args is not \'a\'');
          }
      } 

- free switch
#
    let u = 'u';
    switch(u){
        case 'u':{
            console.log( 'args is \'u\'' );
        }
            break;
        default:{
            console.log( 'args is not \'u\'' );
            u = 'u';
            console.log('fixed => u = \'u\' ')
        }

    }

## operator precedence

The following table is ordered from highest (21) to lowest (1) precedence.


[Operator_Precedence](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence)

<font color='red'>test blue color font</font>

<font color='green'>test blue color font</font>

<h1><font color = 'orange'>orange</font></h1>
<h1><font color = 'goldenrod'>goldenrod</font></h1>
<h1><font color = 'blue'>blue</font></h1>
<h1><font color = 'green'>green</font></h1>
<h1><font color = 'forestgreen'>forestgreen</font></h1>
<h1><font color = 'teal'>teal</font></h1>
<h1><font color = 'royalblue'>royalblue</font></h1>
<h1><font color = 'lime'>lime</font></h1>
<h1><font color = #ff00ff>#ff00ff</font></h1>
<h1><font color = 'navy'>navy</font></h1>
<h1><font color = 'crimson'>crimson</font></h1>
<h1><font color = 'maroon'>maroon</font></h1>
<h1><font color = 'sienna'>sienna</font></h1>
<h1><font color = 'olive'>olive</font></h1>
<h1><font color = 'darksalateblue'>darksalateblue</font></h1>
<h1><font color = 'lavender'>sdcs</font></h1>
<h1><font color = 'lavender'>sdcs</font></h1>
<h1><font color = 'lavender'>sdcs</font></h1>
<h1><font color = 'lavender'>sdcs</font></h1>
<h1><font color = 'lavender'>sdcs</font></h1>
